Layer 2 traffic, by its very nature, has presented certain challenges to creating Data Center (DC) interconnects. Notably, Layer 2 offers limited capabilities in terms of directing and controlling traffic, redundancy, multicasting, and the like. To address these limitations, a number of technologies have arisen in recent years, such as Overlay Transport Virtualization™ (OTV) from Cisco Systems, Inc., Virtual Private Local Area Network Service (VPLS), G.8032, and the like.
One promising technology to implement DC interconnects is Ethernet virtual private network (EVPN) technology. In general, an EVPN instance includes any number of customer edge devices (CEs), such as hosts, routers, switches, etc., and any number of provider edge devices (PEs) that are part of a Multiprotocol Label Switching (MPLS) infrastructure. During operation, the EVPN PEs provide virtualized, bridged Layer 2 connectivity between the CEs. Multiple EVPN instances can also be instantiated in a provider network, as well.